In general, flexible display devices, which are manufactured by forming a display on a flexible substrate to provide flexibility, are very advantageous in that they can be bent or flexed as needed. Such flexible display devices are expected to be a next-generation display device to replace portable computers, electronic newspapers, smart cards, and print media such as books, newspapers, and magazines.
Meanwhile, flexible display devices should normally maintain display performance when they are bent, but exhibit poor display performance according to bending degree.
In particular, in the case of flexible display devices, an electric device (e.g., a thin-film transistor structure) is formed on a flexible substrate. Accordingly, when a flexible display device is greatly bent, stress due to such bending is transmitted to an electric device, whereby cracks occur in the electric device or the properties of the electric device are deteriorated. These problems can become more serious when the flexible display device is excessively or repeatedly bent or the area thereof is enlarged, resulting in decrease in lifespan and reliability of the flexible display device.